CHAPTER 2
PRODUCT FEATURES
2.1 Description
The Infrared Thermometer Model CA879 is a non-contact temperature measuring
instrument. It provides precision measurement with its laser target feature.
To measure the temperature of an object, simply point the gun at the surface of the
object and the temperature will appear on the digital display. The thermometer has
an automatic shut-off feature. Shut-off will occur approximately 10 seconds after
the trigger is released.
2.2 Emissivity
All objects whose temperature is higher than absolute zero (-273.15°K) emit infra-
red energy. This energy radiates in all directions at the speed of light. When the
gun is pointed at an object, the probe's lens senses this energy and focuses it onto
an infrared detector comprised of a thermocouple stack. The detector produces a
voltage signal proportional to the amount of energy received, and therefore propor-
tional to the object's temperature.
Certain objects emit infrared energy, but also reflect it. Unlike matt surfaces, shiny
or highly-polished surfaces tend to reflect energy. This reflection is represented by
a factor called emissivity, which may vary from 0.1 for a highly reflective object to
1 for a flat black object. In the case of the Model CA879 thermometer, the emis-
sivity is preset at 0.95, the most frequent value, enabling approximately 90% of all
applications to be covered.
5
Infrared Thermometer Model CA879